Specific solvent effect on the photophysical behavior of substituted chromones: A combined fluorescence, DFT and MD study

Water-soluble optical sensors: keys to detect aluminium in biological environment

Metal ion plays a critical role from enzyme catalysis to cellular health and functions. The concentration of metal ions in a living system is highly regulated. Among the biologically relevant metal ions, the role and toxicity of aluminium in specific biological functions have been getting significant attention in recent years. The interaction of aluminium and the living system is unavoidable due to its high earth crust abundance, and the long-term exposure to aluminium can be fatal for life. The adverse Al3+ toxicity effects in humans result in various diseases ranging from cancers to neurogenetic disorders. Several Al3+ ions sensors have been developed over the past decades using the optical responses of synthesized molecules. However, only limited numbers of water-soluble optical sensors have been reported so far. In this review, we have confined our discussion to water-soluble Al3+ ions detection using optical methods and their utility for live-cell imaging and real-life application.

Deciphering Spectroscopic and Structural Insights into the Photophysical Behavior of 2,2'-Dipyridylamine: An Efficient Environment Sensitive Fluorescence Probe

Excited state deactivation properties and the effects of solvent hydrogen bonding (HB) on the photophysical behavior of 2,2'-dypyridylamine (DPyA) were investigated by steady state and time-resolved fluorescence experiments, molecular docking, and density functional theory (DFT) calculations. In addition to the polarity effect, the contributions of solvent HB donation (HBD) acidity and HB acceptance (HBA) basicity to modulate the solvatochromic spectral properties were estimated from multiparametric linear regression analysis using Kamlet-Taft (KT) and Catalán formalisms. The importance of C-N bond torsion, leading to the trans → cis conversion, was manifested by substantial increase in DPyA fluorescence yield in the presence of cyclodextrin (CD) and glycerol. The unusually low fluorescence yield in aqueous medium was explained on the basis of synergistic effect of solvent hydrogen bonding combined with excited state conformational isomerization, which renders DPyA to be an excellent environment sensitive fluorescence reporter. The experimental results were verified with structural insights obtained from DFT calculations at B3LYP/6-311++G(d,p) level and construction of potential energy surface (PES) in the ground state as well as in the excited states.

Fluorescence solvatochromism and modulated anticholinergic activity of novel coumarin compounds sequestered in human serum albumin nanocavities

The antagonistic effect of the HSA matrix towards the acetylcholinesterase inhibition potencies of novel coumarin compounds is probed by multi-spectroscopic techniques.